PHP alone does not have the ability to leverage the GPU. This was recently discussed on the php internals developer list.
Keep in mind that GPUs excel at certain types of workloads, while they're not that great for others. PHP wouldn't be able to really take advantage of GPU acceleration because the work it performs isn't really the best kind for a GPU.
If you really want to play with HipHop and random high performance stuff, you might want to begin following Open Parallel. They've been working with an Intel technology called Threading Building Blocks and have been integrating it into HipHop by adding new functions that can call callbacks asynchronously, with outstanding results. There was a great deal of interest when they introduced their work to the HipHop group.
However, there is no sign whatsoever of CUDA support, or really any GPU support at all in HipHop. To be honest, HipHop is not the right solution for the majority of PHP users. If you are trying to squeeze performance out of code, you should be profiling it.
与恶龙缠斗过久,自身亦成为恶龙；凝视深渊过久,深渊将回以凝视…
